1. Field of the Invention
The present invention generally relates to a projection-electrode fabrication method and a semiconductor device including a projection electrode, and more particularly, to a fabrication method of the projection electrode which is utilized for a flipchip-mounting method or a tape-automated bonding (TAB) method.
Recently, to meet demands for miniaturization, high speed, and high-density mounting in a computer, establishment of a fabrication technology for a semiconductor device, having features of a fine pitch and a multipin, is required, and a semiconductor device providing low cost as well as meeting the above demands, is further desired.
As methods capable of mounting a multipin semiconductor device with low cost, the flipchip-mounting method and the TAB method are well known. In the flipchip-mounting method and the TAB method, projection electrodes such as bumps are formed on the semiconductor device, and via these projection electrodes the semiconductor device is connected with a mounting substrate or a TAB tape.
Therefore, to mount the multipin semiconductor device at low cost, the projection electrodes need to be fabricated with high efficiency and at low cost.
2. Description of the Prior Art
In a conventional projection-electrode fabrication method which is used for the flipchip-mounting method and the TAB method, first a circuit is formed in the semiconductor device, and next projection electrodes are fabricated on electrode pads which have been formed in that semiconductor device. In further detail, on the electrode pads which have been formed in the semiconductor device, the projection electrodes are fabricated by means of an evaporation method by an electrolysis plating method and a sputtering system, etc., being implemented for lithographic technologies.
It is noted that in a conventional fabrication method of the projection electrode, after a series of the semiconductor-device fabrication process for fabricating the semiconductor device is completed, a projection-electrode fabrication process is independently carried out to form the projection electrodes.
Therefore, in the conventional fabrication method of the projection electrode, the projection electrodes are fabricated by using the lithographic technology after the forming of the circuit in the semiconductor device, consequently such a process as using a lithographic technology is implemented twice for forming the circuit in the semiconductor device and for fabricating the projection electrodes on the circuit. Thus, from a standpoint of total fabrication procedures of the semiconductor device, a large number of procedures, much equipment and a long processing time are required, so that it may cause the device cost to increase.